Justification:
This highly specialised species is a palaeoendemic of Corsica and the sole representative of the genus Tyrrhenaria worldwide. It is today restricted to a very narrow distribution area which is highly fragmented, suggesting a genetic impoverishment and unforeseeable events. Moreover, 40% of the population is located on a 0.0051 km² area surrounded by the airport and the beach. These facts justify the maintenance of the species in the category Critically Endangered (CR B1ab(i,ii,iii)+2ab(i,ii,iii)).

The Corsican Snail is only found near Ajaccio, in a biotope restricted to a small geographic area named "Campo dell'Oro" (which really occupies only 0.02 km²), located near the airport, delimited at the east side by the joint delta of the two rivers Gravona and Prunelli and at the west side by a marina.

Thanks to human assistance and biotope management (Natura 2000 site) providing protected areas appropriate for snail colonization, the population is considered to be stable. The population size is estimated to be between 7,500 and 10,000 individuals among which 3,800–5,200 are mature individuals (estimated information from samplings made in 2009–2010, M. Charrier, pers. comm., 2011)

The species is ecologically and biologically highly specialised and lives on and in the loose maritime sands of the river delta associated with low shrub vegetation (including Genista salzmannii) and with annual or biennial plants characteristic of coastal sands.